Too much time on my hands, but....Has anyone ever succeeded in changing the set point of a voltage regulator? Presumably it would be by soldering on an upgraded regulator component to the brush carrier.. I had been looking for a replacement VR with a higher set point than 14.0, but now kind of given up
Voltage Regulator
- Thread starter romanrob
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Yes, just unscrews and screws in the top of the alternator on the oil burner. Think mine is now 14.5V. Tomcat put a link up. Cost around £15.
brianp38dse
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If you have the doozel p38 this is the one 14.7 v
http://rover.ebay.com/rover/1/710-5...681762?hash=item5207c53062:g:xoYAAOSwHZBelHGJ
http://rover.ebay.com/rover/1/710-5...681762?hash=item5207c53062:g:xoYAAOSwHZBelHGJ
Sadly I don't have a diesel... two thirsty V8s, with Magneti Marelli alternators. I can find a 14V one ie standard, but that's not much use, as my current ones deliver 14V (on a good day) - the higher set point for AMR 4247 and AMR 2938 seems elusive however, hence I was thinking of getting my soldering iron out, assuming it's not a fools errand
brianp38dse
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Ow well worth a try , some of the others might know for the v8`s.
Henry_b
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14.7V seems a bit on the high side.
The early p38s had a different alternator that charged at around 13.8V but when later cars were fitted with batteries with a higher Calcium content that can withstand a higher charge voltage the alternator fitted to later cars tend to regulate at around 14.2V.
"mine does"
Assuming you have a proper battery fitted a regulator to 14v shouldn't be an issue..
The early p38s had a different alternator that charged at around 13.8V but when later cars were fitted with batteries with a higher Calcium content that can withstand a higher charge voltage the alternator fitted to later cars tend to regulate at around 14.2V.
"mine does"
Assuming you have a proper battery fitted a regulator to 14v shouldn't be an issue..
Tnx Henry, 14 V has always worked for me, but since I don't get out much these days with coronavirus a slightly better set point wd be useful when I do - so I just thought it might be an easy fix to get 14.something, or someone might have blazed a trail before me. I have Bosch S4 batteries - allegedly Pb-Ca.
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Sadly battery makers never told Joe public that the old standard 13.8 volt charge rate was as useful as tits on a Mars bar for use with calcium batteries. Even half calcium half antimony would sulphate up over time as they never got fully charged. Full calcium have no chance and will sulphate up PDQ. 14.7 should be enough for half calcium but no good for full calcium. Unless you have a automatic recovery charger you can use now and again to knock the sulphate off. They will usually stick 18 volts or more through the battery for a period of time then drop to maintenance charge rate. Cycling until they have done their trick. Sometimes full calcium batteries get so bad they are unrecoverable. Simple reason for calcium batteries is they retain their charge longer sitting in storage in the battery shop and do not need to be maintenance charged on a regular basis like lead acid do.
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Datatek
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14.7 volts is the standard for modern automotive batteries, some newer cars have smart alternators that charge at 15.8 volts for a predetermined period. The regulator is a sealed unit these days, so hard to modify. In the old days, the output could be modified simply by adding a diode. You can get external regulators with various set point voltages, used them a lot on boats.
Datatek
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L/C do not need topping up in service either.
Tnx. The answer seems tantalisingly close.. both my VR assemblies have a four-legged silver-capped voltage regulator component in the middle - if I had the right replacement I cd just solder them in... Still, I'll probably never find the right component so I'll just buy the 14V set point and see if new beats old. Tnx for your help
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I thought the one off the Thor had a 14.2 or 14.5V setpoint and was a straight swap? I'm sure it had more windings and put out more power.
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No, just the 120A. The 150A only fits the Thor version.
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I replaced the whole alternator. Not a Magnetti one! I can't remember the make, but it came from Island 4x4.
For any V8 owners following, the Mobiletron Vr-F153a fits an AMR 4247 100A A127 and has a 14.7v set point. A Transpo IX123 fits, but Std set point...
My learning was to avoid using the LR part numbers to find a VR that merely "fits" but to dig deeper on the websites of the after-market manufacturers to find the right one and then search ebay using their own part code.
Hope it helps someone.
My learning was to avoid using the LR part numbers to find a VR that merely "fits" but to dig deeper on the websites of the after-market manufacturers to find the right one and then search ebay using their own part code.
Hope it helps someone.
brianp38dse
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I think we need to put the part numbers for these regulator all together in the tech archive, it might make it easier to find.
Datatek
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It's a bit premature as I have to test another one, I purchased 2 of the Mobiletron regulators for the Valeo alternator used on the diesel purchased as having a 14.7 set point. The one I have fitted on the car is giving me 13.8 volts, I have not had time to investigate if this is a high resistance connection or a regulator that actually has a 13.8 volt set point not the 14.7 it was sold as having.
Anyone fitting one should double check the voltage at the battery with the engine at 2K rpm.
